IRVING — Mackenzy Bernadeau and Nate Livings, the veteran guards added by the Dallas Cowboys, played in only one preseason game together. That wasn’t with starting center Phil Costa.

And the starting tackles, Tyron Smith and Doug Free, have switched sides since last season.

So after the Cowboys revamped their offensive line during the offseason, including new position coach Bill Callahan, the first time the group will play together protecting Tony Romo will be in the NFL’s kickoff game Wednesday night.

And that will be against the defending Super Bowl champion New York Giants and their standout defensive front of Justin Tuck, Jason Pierre-Paul and Osi Umenyiora.

“They’re very disruptive, and they just have a lot of guys they can throw at you with the great bursts, great energy,” Romo said. “They do some different things with their technique that really allow them to disrupt offenses. And without getting into detail, I think that can provide you with some difficult situations, and so we just have to do some different things to help that.”

On top of their line changes, the Cowboys were still uncertain of the status of tight end Jason Witten (lacerated spleen). The seven-time Pro Bowler again had limited participation in practice Monday, three weeks after he got hurt in the preseason opener and a day before a CT scan that will determine if his spleen has healed enough to be cleared to play.

Livings, who came from Cincinnati, said the linemen haven’t focused on the time they missed because of various injuries, but rather on the time they’ve had together. And he described that as awesome.

“Whether it’s five, 10 minutes, 15 hours, the time we have together is the time we have together. You can’t look on the time we are not together,” Livings said. “It’s just about getting out there, focusing on what we got and getting the job done.”

One of the offseason goals for the Cowboys was to add some experienced bulk in the middle of the line. They gave multiyear contracts to free agents Livings and Bernadeau, both listed at 6-foot-4 and 320 pounds and going into their fifth NFL season.

But Bernadeau missed the entire offseason and the start of training camp after hip and knee surgeries. Then Livings suffered a hamstring injury in camp.

“We signed these guys for a reason,” coach Jason Garrett said. “When they’ve been healthy, they’ve done a real nice job for us. It’s our good fortune, they’ve been healthy the last couple of weeks. ... We’re excited to see them play together against a really, really formidable defensive line the Giants have.”

As for the tackles, Smith moved to the left as Romo’s blind-side protector after starting all 16 games as a 20-year-old rookie on the right side, where Doug Free returned.

While Costa is the only line starter in the same spot as last season, the Cowboys went into camp with every intention of giving the 16-game starter competition for the job. But Bill Nagy and Kevin Kowalski both sustained ankle injuries, ensuring Costa kept the job even after being sidelined himself.

Costa was the only expected starter on the entire roster to play in the preseason finale Wednesday against St. Louis. He got 12 snaps after missing the first three preseason games and time in camp because of back stiffness.

“We are just happy to have Phil back and to have everybody getting the reps now with one another. ... We are at least taking advantage of all the reps we are now getting,” said Bernadeau, who came to the Cowboys from Carolina. “We are just focused now on protecting Romo, improving our running game. It all just comes with reps. Communication is the key. Phil does a great job of leading the line. We are getting better every day.”

But there were only a few days for them to be together on the field for practice.

The next time they put the pads on will be for that unprecedented midweek opener, a game preceded by the Giants marking their second Super Bowl championship in five years. It will be the Cowboys’ first game since their season-ending 31-14 loss at MetLife Stadium on New Year’s Day that clinched the NFC East title and league’s last playoff spot for the Giants.

“We got a lot of stuff going on trying to figure out what kind of looks we’re going to get,” said Tuck, one of the Giants’ ends. “Some of the guys we know very well. Some of the guys we don’t know at all. For the most part it’s going to come down to playing our keys throughout the game, make sure we play everything straight up and trying to get a feel for them early in the football game.”